The present invention relates to a digital broadcasting system, particularly to a digital broadcasting system having a compression processing circuit for transmitting and receiving a plurality of pictures.
A conventional system used for providing a broadcasting service regarding video pictures transmits the pictures over a transmission line of a single channel picture by picture, receives the transmitted pictures at a tuner picture by picture, and selects any picture to be displayed.
In other words, the conventional broadcasting system mentioned above requires a transmission line of a single channel for each picture in order to simultaneously transmit a plurality of pictures.
In order to provide simultaneous transmission of two different pictures, for example, transmission lines of two channels are necessary, leading to a problem that the transmission lines occupy twice the band required for transmission of one picture.
On the other hand, the receiving end requires two tuners for receiving these different pictures.
Further, if the pictures are synchronized with each other, the receiving end needs to carry out a process for synchronizing the pictures that are separately received.
A resultant problem is that the broadcasting service to be implemented for simultaneously providing two synchronized pictures has its facilities and circuit structure that are significantly complicate and large-scale, compared with the ordinary broadcasting service.
Accordingly, the present invention aims to provide a digital broadcasting system capable of efficiently transmitting and receiving pictures of two channels.
The invention further aims to provide a digital broadcasting system which does not need a synchronizing process when synchronized pictures of two channels are transmitted and received.
The invention still further aims to provide a digital broadcasting system capable of achieving those aims with simple facilities and circuit structure.
According to the invention, a digital broadcasting system includes a picture processing circuit generating picture data of one channel using a first picture signal and a second picture signal, a transmission circuit compressing and modulating the picture data and then transmitting the picture data, a reception circuit receiving the transmitted picture data, and demodulating and expanding the picture data, and a picture reproducing circuit receiving the demodulated and expanded picture data to reproduce the first and second picture signals.
An advantage of the invention thus resides in efficient transmission and reception of two picture data over a transmission line of one channel.